I made up my mind long ago to follow one cardinal rule in all my writing — to be clear.

Early in my school career, I turned out to be an incorrigible disciplinary problem. I could understand what the teacher was saying as fast as she could say it, I found time hanging heavy, so I would occasionally talk to my neighbor. That was my great crime, I talked in school.

The energy requirements for interstellar travel are so great that it is inconceivable to me that any creatures piloting their ships across the vast depths of space would do so only in order to play games with us over a period of decades. If they want to make contact, they would make contact; if not, they would save their energy and go elsewhere.

Any book worth banning is a book worth reading.

I'm not a speed reader. I'm a speed understander.

And [Asimov]'ll sign anything, hardbacks, softbacks, other people's books, scraps of paper. Inevitably someone handed him a blank check on the occasion when I was there, and he signed that without as much as a waver to his smile — except that he signed: 'Harlan Ellison.

On Earth, we are unmanned by our longing for a pastoral past that never really existed; and that, if it had existed, could never exist again...on the Moon, there is no past to long for or dream about. There is no direction but forward.